Friction clamp

ABSTRACT

A clamp formed from two identical clamp members interconnected by an adjustable bolt which passes through them. The clamp is actuated by a pair of rotary cams journalled in cylindrical recesses in opposed faces of the clamp members, the cams having convex interengaging cam faces so that when rotated together in contact they spread the clamp members at one end of the clamp and thereby close the ends at the other end of the clamp. This arrangement is of particular value in the repair of automobile bodies which have been damaged, since a sheet of metal can be engaged either at the end or at the side of the clamp, or the clamp members may be located one on each side of a sheet of metal and bolted together through the sheet. In a variant, adjustable jaws are provided on the clamp to facilitate the lifting of blocks of material of varying widths.

United States Patent 91 Jackson 14 1 July 10, 1973 FRICTION CLAMP [76]Inventor: Robert Alvin Jackson, 6565 Aubrey St., Burnaby, BritishColumbia, Canada [22] Filed: Jan. 28, 1972 [21] Appl. No.: 222,066

[52] US. Cl 294/116, 294/94, 29/267 [51] Int. Cl B25b 5/08 [58] Field ofSearch 294/94, 95, 102,

294/106,116;24/134 R, 134 E, 134 L, 134 M, 134 P, 134 CP, 248 E; 29/238,258, 261,

Primary Examiner-Evon C. Blunk Assistant Examiner.lohnny D. CherryAttorney-Kellard A. Carter [5 7 ABSTRACT A clamp formed from twoidentical clamp members interconnected by an adjustable bolt whichpasses through them. The clamp is actuated by a pair of rotary camsjournalled in cylindrical recesses in opposed faces of the clampmembers, the cams having convex interengaging cam faces so that whenrotated together in contact they spread the clamp members at one end ofthe clamp and thereby close the ends at the other end of the clamp. Thisarrangement is of particular value in the repair of automobile bodieswhich have been damaged, since a sheet of metal can be engaged either atthe end or at the side of the clamp, or the clamp members may be locatedone on each side of a sheet of metal and bolted together through thesheet.

In a variant, adjustable jaws are provided on the clamp to facilitatethe lifting of blocks of material of varying widths.

9 Claims, 7 Drawing Figures FRICTION CLAMP The invention relates toclamps of the kind utilizing camming means for applying clampingpressure and particularly to such clamps for use in the repair of bodywork of road vehicles.

Clamps utilizing a camming action to operate them are known, twoexamples being disclosed in US. Pat. No. 2,383,078 to Pringle and No.3,318,630 to Bryant. In such earlier constructions, as exemplified byPringle and Bryant however, the clamp is only capable of use inproviding an end pull since the only surfaces capable of clamping actionare those of the actual jaws themselves. The unit construction used inthe manufacture of modern automobiles is of a nature which necessitatesthe application of clamps in a manner other than to provide a direct endpull when repair work is being carried out. The earlier clamps discussedabove are inappropriate for such work.

It is among the objects of the present invention to provide a clampwhich is versatile in use and which can be used in various ways as willbe described below in the repair of automobile bodies.

The invention therefore provides a clamp comprising a pair of clampmembers presenting opposed clamping jaws at one end of the clamp andopposed journal means for rotatable cams at the other end of the clamp,means providing a fulcrum between the jaws and journal means for each ofsaid clamp members, and opposed cams journalled in said journal means,said cams having interengaging convex cam faces for causing a spreadingmovement of said other ends of said clamping members when rotated froman inoperative position.

The invention will now be described by way of exam pie with reference tothe accompanying drawing in which;

FIG. 1 is a plan view on a clamp according to the invention,

FIG. 2 is a perspective view of one of the cams forming part of theconstruction of FIG. 1,

FIG. 3 is a section on the line 3--3 of FIG. 1,

FIG. 4 is an elevation of part of a vehicle body showing three modes ofuse of the clamp according to the invention,

FIG. 5 is a plan view of a modified embodiment of the invention,

FIG. 6 is a plan view of a third embodiment of the invention, and

FIG. 7 is a sectional elevation on the line 7-7 of FIG. 6.

Referring first to FIGS. 1 to 3 of the drawings, the clamp 1 showncomprises two identical members 2 hav ing serrated jaws 3 at one end andinterconnected by a bolt 4 upon which a nut 5 is engaged for adjustment.The bolt 4 passes through bores 6 in the members 2.

At the ends of the members 2 remote from the jaws 3, the members 2 areprovided with semi-cylindrical opposed recesses 7 forming journals for apair of rotary cams 8. The cams 8 have cylindrical surface portionsengaging the recesses 7 and convex interengaging cam faces 9. As bestseen in FIG. 3, the ends of the members 2 remote from the jaws 3 arebifurcated at 10, the bifurcation 10 intersecting the recesses 7 atright angles thereto. Each of the cam members 8 has an operating lever11 extending from the mid point thereof outwardly through thebifurcation 10 in the corresponding clamp member. A notch 12 is providedin the end of each of the levers 11 to facilitate engagement with amember such as chain 13 for applying leverage.

In use, the bolt and nut 4 and 5 are first adjusted to facilitateengagement of the clamping members 2 over the element to be clamped.After such engagement has been effected, leverage is applied to thelevers 11 so as to rock the cams 8 simultaneously. This effects aspreading movement of the ends of the members 2 remote from the jaws 3so that a clamping action is effected. During this movement, the innerfaces of the bolt head and the nut 5 act as fulcrums for the members 2.

Referring now to FIG. 4, a vehicle body 15 is shown to which has beenattached three clamps of the kind described above with reference toFIGS. 1 to 3. Clamp 16 has been attached to an edge strip on the vehiclebody by means of the jaws 3 so as to provide an end pull. Clamp 17 hasbeen applied so as to engage an edge strip of the vehicle body betweenthe sides of the clamp. With this arrangement, the edge strip of thevehicle body is engaged not only between the jaws 3 but also between thefaces 9 of the cams 8. This arrangement facilitates a pull generallyparallel with the element which is being gripped. The clamp 18 shown inFIG. 4 has been attached to a body work portion remote from the edgestrips. To facilitate such attachment, the clamp is dismantled andreassembled with one of the clamp members 2 on each side of the sheet tobe clamped and resecured by the bolt which passes through the clampmembers and also through an aperture formed in the sheet.

It will be seen that the clamp of the invention is versatile in use andis capable of practical application in ways not possible with earliercam action clamps such as those of Pringle and Bryant.

FIG. 5 shows a second embodiment which is generally similar to that ofFIGS. 1 to 3 and similar parts are referred to by the same referencenumeral. In the case of FIG. 5 however the notches 12 are omitted fromthe operating levers 11. In this embodiment, a pair of secondaryoperating levers 20 are each pivoted at one end 21 t0 the end of thelevers 11, the other ends of the levers 20 are pivoted at 22 to a commonlink 23. The link 23 has an eye 24 to facilitate the application of apushing or pulling action. It will be seen that such action will rotatethe cams 8 through the linkage 20 and 11 to result in the clamp 1applying a clamping action.

FIGS. 6 and 7 show a third embodiment of clamp 30 in which a pair ofclamping members 31 are pivoted together at 32 through overlappingtrunnions 33. The members 31 have oppositely projecting perpendicularextensions 34 which are provided with a frictional engaging surface 35on one side. The surface 35 may be grooved or otherwise roughened asdesired. Engaged over the extensions 34 are a pair of adjustable jawmembers 36, each of which is apertured at 37 for reception of anextension 34. A bolt 38 extends in threaded engagement with an aperturein the jaw member 36 so as to project into the aperture 37 for lockingengagement with the extension 34 as best seen in FIG. 7. The inner facesof the jaw members 36 have a hard rubber pad 39 bonded thereto toprovide friction on engagement with the article 40 to be gripped.

The other ends of the clamp members 31 are provided withsemi-cylindrical recesses 7, rotary cams 8 and operating levers 11 whichare identical in construction and assembly with those shown in FIG. 1and will not be referred to further.

When using the clamp of FIGS. 6 and 7, the bolts 38 are first loosenedand the jaws 36 adjusted in spacing so as to accommodate the article 40to be lifted after which the bolts 38 are again tightened. Simultaneousleverage is then applied to the levers 11 in the same manner as in FIG.1 so that the ends of the members 31 remote from the jaws 39 are spreadoutwardly. This effects a clamping action by the pads 39 on the article40 which can then be lifted.

It will be seen that the invention provides a clamping mechanism relyingon the spreading action of a pair of rotary cams which is versatile inuse and application. It will be appreciated that other fields of use areappropriate for the invention. For example, the camming device couldreadily be applied as a mechanism to actuate a disc brake caliber.

I claim:

1. A clamp comprising a pair of clamp members presenting opposedclamping jaws at one end of the clamp and opposed part cylindricalrecesses forming journal means for rotatable cams at the other end ofthe clamp, means providing a fulcrum between the jaws and recesses foreach of said clamp members, and opposed rotatable cams having partcylindrical bearing surfaces received in said recesses, said cams havinginterengaging convex cam faces for causing a spreading movement of saidother ends of said clamping members when rotated in said recesses froman inoperative position.

2. A clamp as claimed in claim 1, wherein said clamp members are formedwith substantially flat opposed surfaces and wherein said meansproviding a fulcrum comprises an adjustable bolt extending through saidclamp members, whereby said flat opposed surfaces can be broughtsubstantially into mutual contact.

3. A clamp as claimed in claim 1, wherein said clamp members arebifurcated at said other ends in a direction at right angles to saidpart cylindrical recesses,and wherein said cams each further comprise anoperating lever extending from said cylindrical bearing surface.

4. A clamp as claimed in claim 3, wherein said operating levers are eachnotched at their ends'for engagement with means to apply leverage.

5. A clamp as claimed in claim 3 and further comprising a pair ofsecondary operating levers pivoted one to each of said first mentionedlevers and a common link to which each of said secondary levers ispivoted for causing simultaneous equal rotation of said cams throughsaid first mentioned and secondary levers.

6. A clamp as claimed in claim 1, wherein said clamp members compriseoppositely extending perpendicular extensions at said one end of theclamp, and a pair of jaw members adjustably mounted on said extensions.

7. A clamp as claimed in claim 6, wherein said jaw members comprise apair of longitudinal elements apertured for engagement over saidextensions, a pair of locking bolts extending through said element wallsfor engagement with said extensions.

8. A clamp as claimed in claim 7, wherein said jaw members furthercomprise friction pads bonded to their opposed surfaces.

9. Means for effecting a controlled spreading movement between twoopposed members, comprising opposed part cylindrical recesses formingcam journal means provided on said members, opposed rotatable camshaving part cylindrical bearing surfaces received in said recesses, saidcams having interengaging convex cam faces, and means for causingrotation of said cams in said recesses to effect said spreadingmovement.

1. A clamp comprising a pair of clamp members presenting opposedclamping jaws at one end of the clamp and opposed part cylindricalrecesses forming journal means for rotatable cams at the other end ofthe clamp, means providing a fulcrum between the jaws and recesses foreach of said clamp members, and opposed rotatable cams having partcylindrical bearing surfaces received in said recesses, said cams havinginterengaging convex cam faces for causing a spreading movement of saidother ends of said clamping members when rotated in said recesses froman inoperative position.
 2. A clamp as claimed in claim 1, wherein saidclamp members are formed with substantially flat opposed surfaces andwherein said means providing a fulcrum comprises an adjustable boltextending through said clamp members, whereby said flat opposed surfacescan be brought substantially into mutual contact.
 3. A clamp as claimedin claim 1, wherein said clamp members are bifurcated at said other endsin a direction at right angles to said part cylindrical recesses, andwherein said cams each further comprise an operating lever extendingfrom said cylindrical bearing surface.
 4. A clamp as claimed in claim 3,wherein said operating levers are each notched at their ends forengagement with means to apply leverage.
 5. A clamp as claimed in claim3 and further comprising a pair of secondary operating levers pivotedone to each of said first mentioned levers and a common link to whicheach of said secondary levers is pivoted for causing simultaneous equalrotation of said cams through said first mentioned and secondary levers.6. A clamp as claimed in claim 1, wherein said clamp members compriseoppositely extending perpendicular extensions at said one end of theclamp, and a pair of jaw members adjustably mounted on said extensions.7. A clamp as claimed in claim 6, wherein said jaw members comprise apair of longitudinal elements apertured for engagement over saidextensions, a pair of locking bolts extending through said element wallsfor engagement with said extensions.
 8. A clamp as claimed in claim 7,wherein said jaw members further comprise friction pads bonded to theiropposed surfaces.
 9. Means for effecting a controlled spreading movementbetween two opposed members, comprising opposed part cylindricalrecesses forming cam journal means provided on said members, opposedrotatable cams having part cylindrical bearing surfaces received in saidrecesses, said cams having interengaging convex cam faces, and means forcausing rotation of said cams in said recesses to effect said spreadingmovement.